我正在尝试示例应用。我正在从sqlite db填充listview数据。数据库存储在assets文件夹下。 Log cat显示DB无法打开。我的数据库名称“mydb”，包含一个表：“月”和三列：jan，feb和march。
检查我的代码：
MainActivity.java
package test.lin.com.presqlitedb;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.TextView;
public class MainActivity extends ActionBarActivity {
private ListView lstMonthList;
private java.util.List<MonthObj> lst_Month_list = new java.util.ArrayList<MonthObj>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
DBHelper dbHelper = new DBHelper(getApplicationContext());
lstMonthList = (ListView) findViewById(R.id.listView);
lst_Month_list = dbHelper.getMonth();
lstMonthList.setAdapter(new LAdapter());
}
public class LAdapter extends BaseAdapter {
@Override
public int getCount() {
// TODO Auto-generated method stub
return lst_Month_list.size();
}
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return lst_Month_list.get(position);
}
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
final ViewHolder holder;
final int pos;
LayoutInflater inflater = getLayoutInflater();
pos = position;
if (convertView == null) {
convertView = inflater.inflate(R.layout.row, null);
holder = new ViewHolder();
holder.txtJan = (TextView) convertView.findViewById(R.id.textView1);
holder.txtFeb = (TextView) convertView.findViewById(R.id.textView2);
holder.txtMarch = (TextView) convertView.findViewById(R.id.textView3);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
holder.txtJan.setText(lst_Month_list.get(position).getJan());
holder.txtFeb.setText(lst_Month_list.get(position).getFeb());
holder.txtMarch.setText(lst_Month_list.get(position).getMarch());
return convertView;
}
private class ViewHolder {
TextView txtJan;
TextView txtFeb;
TextView txtMarch;
}
}
}
DBHelper.java
package test.lin.com.presqlitedb;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
public class DBHelper extends SQLiteOpenHelper {
public static String DATABASE_NAME = "mydb";
public static String DATABASE_PATH = "/data/data/test.lin.com.presqlitedb/databases/";
private SQLiteDatabase myDataBase;
private static String myPath = DATABASE_PATH + DATABASE_NAME;
public static final String DATABASE_TABLE = "month";
private static final int DATABASE_VERSION = 1;
public static final int ver = 1;
private SQLiteDatabase db;
Context context;
public DBHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
this.context = context;
if (checkDataBase()) {
openDataBase();
Log.i("run", "open db");
} else {
try {
copyDatase();
openDataBase();
} catch (Exception ex) {
}
}
}
private void copyDatase() throws IOException {
// Open your local db as the input stream
InputStream myInput = context.getAssets().open(DATABASE_NAME);
// Path to the just created empty db
String outFileName = DATABASE_PATH + DATABASE_NAME;
// Open the empty db as the output stream
OutputStream myOutput = new FileOutputStream(outFileName);
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer)) > 0) {
myOutput.write(buffer, 0, length);
}
Log.i("run", "copy successful");
// Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
}
public void openDataBase() throws SQLiteException {
// Open the database
db = SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READWRITE);
}
private boolean checkDataBase() {
SQLiteDatabase checkDB = null;
boolean exist = false;
try {
checkDB = SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READONLY);
} catch (SQLiteException e) {
Log.i("db log", "database does't exist");
}
if (checkDB != null) {
exist = true;
checkDB.close();
}
return exist;
}
public void createDataBase() throws IOException {
boolean dbExist = checkDataBase();
if (dbExist) {
this.getWritableDatabase();
}
dbExist = checkDataBase();
if (!dbExist) {
this.getReadableDatabase();
try {
copyDatase();
} catch (IOException e) {
}
}
}
@Override
public void onCreate(SQLiteDatabase arg0) {
// TODO Auto-generated method stub
try {
createDataBase();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
@Override
public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) {
// TODO Auto-generated method stub
}
public java.util.List<MonthObj> getMonth() {
java.util.List<MonthObj> lst_month = new java.util.ArrayList<MonthObj>();
Cursor c = null;
try {
String sql = "select * from month";
c = db.rawQuery(sql, null);
if (c.getCount() > 0) {
c.moveToFirst();
while (!c.isAfterLast()) {
MonthObj obj = new MonthObj();
obj.setJan(c.getString(0));
obj.setFeb(c.getString(1));
obj.setMarch(c.getString(2));
lst_month.add(obj);
c.moveToNext();
}
}
} catch (Exception ex) {
ex.toString();
ex.printStackTrace();
}
return lst_month;
}
}
MonthObj.java
package test.lin.com.presqlitedb;
public class MonthObj {
private String jan, feb, march;
public String getJan() {
return jan;
}
public void setJan(String jan) {
this.jan = jan;
}
public String getFeb() {
return feb;
}
public void setFeb(String feb) {
this.feb = feb;
}
public String getMarch() {
return march;
}
public void setMarch(String march) {
this.march = march;
}
}
activity_main.xml中
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
tools:context=".MainActivity">
<ListView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/listView"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true" />
</RelativeLayout>
row.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Large Text"
android:id="@+id/textView1"
android:layout_alignParentTop="true" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:text="Medium Text"
android:id="@+id/textView2"
android:layout_below="@+id/textView1"
android:layout_alignLeft="@+id/textView1"
android:layout_alignStart="@+id/textView1" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceSmall"
android:text="Small Text"
android:id="@+id/textView3"
android:layout_below="@+id/textView2" />
</RelativeLayout>
logcat的：
01-25 17:00:27.305 5811-5811/? E/SQLiteLog? (14) cannot open file at line 30191 of [00bb9c9ce4]
01-25 17:00:27.305 5811-5811/? E/SQLiteLog? (14) os_unix.c:30191: (2) open(/data/data/test.lin.com.presqlitedb;/databases/mydb) -
01-25 17:00:27.315 5811-5811/? E/SQLiteDatabase? Failed to open database '/data/data/test.lin.com.presqlitedb;/databases/mydb'.
android.database.sqlite.SQLiteCantOpenDatabaseException: unknown error (code 14): Could not open database
at android.database.sqlite.SQLiteConnection.nativeOpen(Native Method)
at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:209)
at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:193)
at android.database.sqlite.SQLiteConnectionPool.openConnectionLocked(SQLiteConnectionPool.java:463)
at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:185)
at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:177)
at android.database.sqlite.SQLiteDatabase.openInner(SQLiteDatabase.java:804)
at android.database.sqlite.SQLiteDatabase.open(SQLiteDatabase.java:789)
at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:694)
at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:669)
at test.lin.com.presqlitedb.DBHelper.checkDataBase(DBHelper.java:82)
at test.lin.com.presqlitedb.DBHelper.<init>(DBHelper.java:34)
at test.lin.com.presqlitedb.MainActivity.onCreate(MainActivity.java:23)
at android.app.Activity.performCreate(Activity.java:5242)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at com.lbe.security.service.core.client.b.x.callActivityOnCreate(Unknown Source)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2162)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2248)
at android.app.ActivityThread.access$800(ActivityThread.java:138)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1199)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5050)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:805)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:621)
at de.robv.android.xposed.XposedBridge.main(XposedBridge.java:132)
at dalvik.system.NativeStart.main(Native Method)
AndroidManifest
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="test.lin.com.presqlitedb">
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme">
<activity
android:name=".MainActivity"
android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
我的完整代码下载链接
https://www.dropbox.com/s/qjmzwwiybs4vvm8/presqlitedb.rar?dl=0
答案 0 :(得分：0)
这是一个错字DATABASE_PATH = "/data/data/test.lin.com.presqlitedb;/databases/"。删除presqlitedb;/databases/
答案 1 :(得分：0)
我已经使用SQLiteAssetsHelper Library解决了这些问题。